Hold-down means for underfloor access housing

ABSTRACT

An underfloor access housing adapted for use with electrical raceway units of the type normally placed in building floors. The access housing spans the distance between adjacent cells and overlies the crests thereof. Separate hold-down means are provided for quickly connecting the access housing to the raceway unit.

United States Patent Fork [45] July 1 1, 1972 s41 HOLD-DOWN MEANS FOR2,402,682 6/1946 Shriro et a] ..248/361 5 UNDERFLOOR ACCESS HOUSING T33}lnvemofl Frank Furl, Allison Park, 3:609:210 9/1971 Guritz ..174/49 [73]Ass1gnee: H. H. Robertson Company, Pittsburgh, Pa. Primal). ExaminerLewiS H. Myers [22] Filed: July 9, 1971 Assistant Examiner-D. A. Tone ppNo: 161,221 AttorneyHarry B. Keck et al.

ABSTRACT [52] US. Cl ..l74/49, 52/221, 248/361 B, An underfloor accesshousing adapted for use with elecuical 174/5 raceway units of the typenormally placed in building floors. [51] Int. Cl. ..H02g 3/04 The accesshousing spans the distance between adjacent cells Field 0f Search 49,52/220, and overlies the crests thereof. Separate hold-down means are248/361 361 B provided for quickly connecting the access housing to theraceway unit. [56] References Cited UNITED STATES PATENTS 9 Chins, 5Drawing Figures 1,429,952 9/1922 Kearney ..248/36IB 1. Field of theInvention This invention relates to an underfloor access housing of thetype known as a pre-set insert which is secured to the crests ofadjacent raceways, and more particularly to improved hold- 1 down meansfor rapidly and effectively connecting the access housing to theadjacent cells.

2. Description of the Prior Art Underfloor access housings of the typewhich span across adjacent cells of an electrical raceway unit are knownin the prior art, see copending application, Ser. No. 822,390 filed May7, 1969, now US. Pat. No. 3,592,956 assigned to the assignee of thepresent invention, and US. Pat. No. 3,303,264 (SAUL et al., Feb. 7,1967). Such access housings have been secured to the raceway unit byspot welding, riveting and like fastening operations. Spot welding is atime time consuming operation requiring skilled personnel and specialequipment. Riveting requires special field operations and is likewisetime consuming.

SUMMARY OF THE INVENTION The principal object of this invention is toprovide improved hold-down means for rapidly and effectively connectingan underfloor access housing to the electrical raceway unit.

A further object of this invention is to provide improved hold-downmeans by which the underfloor access housing is automaticallyelectrically grounded to the electrical raceway unit.

The present invention concerns an electrical access housing adapted foruse with electrical raceway units of the type presenting alternatingcrests and troughs and providing generally parallel enclosed cells. Thecrests of a pair of adjacent cells each have an access opening. Theunderfloor access housing spans across one of the troughs and hasopposite end portions overlying the crests of the adjacent cells. Theaccess housing includes upstanding perimeter walls which enclose thecrest openings and a top wall provided with an outlet opening. Theoverall arrangement is such that access to the interior of the housingmay be gained through the top wall opening from the floor level. Accessbetween the interior of the housing and each of the adjacent cells isprovided by the crest openings.

In accordance with the present invention, separate holddown means isprovided for connecting the access housing to the raceway unit, with theopposite end portions of the access housing disposed in overlyingengaged relation with the crests of adjacent cells. In accordance withone embodiment of the invention, the separate hold-down means arepositioned along the opposite ends of the access housing. The hold-downmeans comprise resilient members having lower ends retained in slotsprovided in the crests of the raceway unit and upper ends hooked overthe top wall of the access housing. The upper end of the resilientmember may present serrations which engage the top wall of the accesshousing and provide effective electrical grounding of the access housingto the raceway unit. The top wall of the access housing may be providedwith beads each of which is engaged by the upper end of the resilientmember thereby to prevent inadvertent disengagement of the resilientmember from the access housing.

In accordance with an alternative embodiment, a tab is provided alongone end of the access housing. The tab extends from the housing andterminates in a downwardly inclined end which is retained by one of theslots. The other end of the housing is retained by means of one of theaforesaid resilient members.

In accordance with a further alternative embodiment, two of theaforesaid tabs are provided along a common side wall of the accesshousing. The ends of the tabs are retained by slots provided in thecrests of the adjacent cells. An additional hold-down means in the formof a resilient member is provided which extends between the accesshousing and the raceway unit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary isometricview, illustrating an electrical access housing secured to an underfloorelectrical raceway unit by the hold-down means of this invention;

FIG. 2 is a cross-sectional view, taken essentially along the line 2-2of FIG. 1, one-half of which illustrates the electrical raceway unitprior to pouring a layer of concrete and the other half of whichillustrates a finished floor structure;

FIG. 3 is an isometric view of a resilient member;

FIG. 4 is a fragmentary, cross-sectional isometric view of a portion ofthe access housing installed over a cell of an electrical raceway unit,illustrating alternative hold-down means; and

FIG. 5 is a fragmentary plan view of the access housing installed overthe raceway unit, illustrating further alternative hold-down means ofthis invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 illustrate acellular floor unit 10 which presents alternating crests 11 and troughs12 and which provides generally parallel enclosed cells 13. The crests11 of adjacent cells 13 have grommetted openings 14 for gaining accessto the interior of the cell 13. The electrical raceway unit 10 may be ofthe type which achieves composite coaction with an overlying layer ofconcrete to produce a floor structure having improved unsupported spancapabilities and improved load carrying capacity. In this instance, theelectrical raceway unit 10 may be provided with indentations 15 in thecrests l1, longitudinal embossments 16in the generally vertical webs l7,and embossments 18 in the valley 19 of each of the troughs 12.

An underfloor access housing 21 is provided which spans across one ofthe troughs l2 and has opposite end portions 22 overlying the crests 11of adjacent cells 13. The access housing 21 presents upstandingperimeter walls including end walls 23a, 23b and side walls 23c, 23d(FIG. 1) which enclose the grommetted crest openings 14 and a top wall24 provided with an outlet opening 25.

In accordance with the present invention, separate holddown means 26 areprovided for rapidly and effectively connecting the access housing 21 tothe adjacent cells 13.

In the preferred arrangement, a slot 27 preferably is provided in thatflat portion 28 of the crest l1 residing between the indentation l5 andthe intersection of the crest 11 with the generally vertical web 17.Each slot 27 is spaced from one of the grommetted openings 14 and one ofthe end walls 23a, 23b of the housing 21. The slots 27 and the openingsin the crest 11 may be formed by a single stamping operation.

Referring to FIG. 3, the present hold-down means also includes aresilient member 29 presenting a tab or lower end 30 below a pair ofshoulders 31 and a hook or upper end 32 which presents serrations 33.The resilient member 29 may be formed from thin gauge spring steel. Theresilient member 29 is installed by inserting the tab 30 into the slot27, as shown in the left-hand side of FIG. 2. Thereafter, the upper end32 is hooked over the top wall 24 of the housing 21, as shown in theright-hand side of FIG. 2. The top wall 24 may be provided with asurface irregularity, such as a bead 34, which is engaged by theserrations 33 thereby to prevent inadvertent disengagement of the upperend 32 from the access housing 21. The spacing 35 (FIG. 3) between thetop surface of the tab 30 and the lower edge of the serrations 33 isless than the spacing 36 (FIG. 2) between the upper surfaces of thecrest 11 and the top wall 24. Thus, the serrations 33 are urged intoengagement with the top wall 24 and provide good electrical grounding ofthe access housing 21 to the raceway unit 10.

The present hold-down means 26 securely retains the housing 21 inposition over the raceway unit 10 during pouring of the concrete 20(FIG. 2). After the concrete 20 has hardened, a suitable decorativecover such as a carpet 37 may be applied over the upper surface of theconcrete 20. A finishing ring 38 may be secured to the mounting ring 39which is carried by the access housing 21.

Alternative embodiments of the present hold-down means are illustratedin FIGS. 4 and 5 wherein corresponding numerals are employed to identifycorresponding parts heretofore described.

FIG. 4 illustrates an alternative hold-down means which may be used inconjunction with one of the hld-down means 26 (FIG. 1). In thisembodiment, one of the hold-down means comprises a tab 40 which may beformed from a portion of the end wall 23b of the access housing 21. Thetab 40 extends outwardly from the end wall 23b and terminates in adownwardly inclined end 41. When installing the access housing 21, thedownwardly inclined end 41 is introduced into the slot 27 of one of thecrests 11. The opposite end of the access housing 21 is connected to thecell by the hold-down means 26, as shown in FIG. 2.

FIG. illustrates a further alternative embodiment wherein two of thetabs 40 extend from the common perimeter side wall 23d and have theirends 41 retained in slots 42 formed in the crests 11 of the raceway unit10. Additional hold-down means in the form of a resilient member 43positioned adjacent to the opposite side wall 230 of the access housing21, extends between the top wall 24 of the housing 21 and the racewayunit 10. The resilient member 43 may, for example, have its lower end 30retained in a slot 44 provided in the valley 19 of the trough 12.Alternatively, the resilient member 43 may, as shown in dash-dotoutline, extend between the access housing 21 and one of the crests 11.

The arrangements illustrated in FIG. 5 permit the use of a larger accesshousing 21' and permits larger diameter grommetted crest openings 45 tobe formed in the crests 11 compare the access housings 21 and 21 and thegrommetted openings 14 and 45 of FIGS. 1 and 5.

It will be appreciated that the present invention provides hold-downmeans by which the access housing may be rapidly and effectivelyconnected to the adjacent cells of an electrical raceway unit. Theconnection is made without the need for field operations heretoforerequired when installing prior art access housings. Moreover, thepresent hold-down means provides automatic electrical grounding of theaccess housing to the electrical raceway unit.

lclaim:

1. In an electrical wiring distributing floor structure includingelectrical raceway units, presenting alternating crests and troughs andproviding generally parallel enclosed cells, the crests of a pair ofadjacent cells each having an outlet opening, an access housing spanningacross one of said troughs and having opposite end portions overlyingthe crests of said pair of adjacent cells, said access housing includingupstanding side walls and end walls enclosing said outlet openings insaid crests and a top wall provided with an outlet opening, theimprovement comprising:

each of said crests having a slot spaced from said access housing; and

separate hold-down means for detachably retaining each of said endportions of said access housing in overlying engaged relation with thecrests of said pair of adjacent cells, each said hold-down means havingan end retained in one said slot.

2. The improvement defined in claim 1 wherein at last one of saidhold-down means comprises a resilient member having a lower end retainedin said one said slot and an upper end hooked over said top wall of saidaccess housing.

3. The improvement defined in claim 2 wherein said upper end presentsserrations engaged with said top wall.

4. The improvement defined in claim 2 wherein said top wall includes atleast one bead which is engaged by said upper end of said resilientmember thereby to prevent inadvertent disengagement of said resilientmember from said access housg The improvement defined in claim 1 whereinat least one of said separate hold-down means comprises a tab having oneend joined to said access housing and an opposite end retained in onesaid slot.

6. The improvement defined in claim 1 including additional hold-downmeans comprising a resilient member extending between said accesshousing and said electrical raceway unit.

7. The improvement defined in claim 6 wherein said resilient member hasa lower end retained in an additional slot formed in one said crest ofsaid adjacent cells.

8. The improvement defined in claim 6 wherein said resilient member hasa lower end retained in an additional slot formed in a bottom wall ofsaid trough.

9. The improvement defined in claim 6 wherein said separate hold-downmeans comprise tabs having corresponding ends joined to a common saidside wall of said access housing and corresponding opposite endsretained in the slots of the crests of said adjacent cells.

1. In an electrical wiring distributing floor structure includingelectrical raceway units, presenting alternating crests and troughs andproviding generally parallel enclosed cells, the crests of a pair ofadjacent cells each having an outlet opening, an access housing spanningacross one of said troughs and having opposite end portions overlyingthe crests of said pair of adjacent cells, said access housing includingupstanding side walls and end walls enclosing said outlet openings insaid crests and a top wall provided with an outlet opening, theimprovement comprising: each of said crests having a slot spaced fromsaiD access housing; and separate hold-down means for detachablyretaining each of said end portions of said access housing in overlyingengaged relation with the crests of said pair of adjacent cells, eachsaid hold-down means having an end retained in one said slot.
 2. Theimprovement defined in claim 1 wherein at last one of said hold-downmeans comprises a resilient member having a lower end retained in saidone said slot and an upper end hooked over said top wall of said accesshousing.
 3. The improvement defined in claim 2 wherein said upper endpresents serrations engaged with said top wall.
 4. The improvementdefined in claim 2 wherein said top wall includes at least one beadwhich is engaged by said upper end of said resilient member thereby toprevent inadvertent disengagement of said resilient member from saidaccess housing.
 5. The improvement defined in claim 1 wherein at leastone of said separate hold-down means comprises a tab having one endjoined to said access housing and an opposite end retained in one saidslot.
 6. The improvement defined in claim 1 including additionalhold-down means comprising a resilient member extending between saidaccess housing and said electrical raceway unit.
 7. The improvementdefined in claim 6 wherein said resilient member has a lower endretained in an additional slot formed in one said crest of said adjacentcells.
 8. The improvement defined in claim 6 wherein said resilientmember has a lower end retained in an additional slot formed in a bottomwall of said trough.
 9. The improvement defined in claim 6 wherein saidseparate hold-down means comprise tabs having corresponding ends joinedto a common said side wall of said access housing and correspondingopposite ends retained in the slots of the crests of said adjacentcells.